JPH0436208Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to an inspection device for inspecting the operating state of a power supply switching device that performs synchronous switching of an inverter bypass power supply, for example, in an uninterruptible power supply system with a bypass power supply. It is.

B. Summary of the invention This is an uninterruptible power supply that switches the power supply to the load between an inverter and a bypass power supply that are connected in parallel to each other using semiconductor switches connected to each power supply, and the switching operation is inspected. When performing this, one semiconductor switch is shorted and power is supplied to the load through the shorted circuit, and both semiconductor switches are supplied with power from one power supply. Under this condition, the power supply is switched and the input of each semiconductor switch is By comparing the voltage and output voltage to check the operation, it is possible to check the switching operation while power is being supplied to the load, regardless of whether there is an abnormality in the switching circuit.

C. Prior Art Figure 3 shows an uninterruptible power supply equipped with a bypass circuit, in which 1 is an inverter, TSi,
TSc is a thyristor switch as a semiconductor switch, and MCCB ₁ to MCCB ₃ are electromagnetic switches. In such devices, the thyristor switch
The power supply is selected between the inverter 1 and the bypass by synchronously switching TSi and TSc on and off. For example, in order to check the synchronous switching operation from the inverter 1 to the bypass, conventionally the synchronous switching from the inverter 1 to the bypass was actually performed to check for abnormalities.

D Problems that the invention aims to solve However, with the conventional inspection method, if, for example, an abnormality occurs in the synchronous switching circuit and the thyristor switch TSc that should be turned on remains off, the power is switched from the inverter to the bypass side. There is a problem in that when the load bus line becomes non-voltage, the power supply to the load is cut off, resulting in a system down.

The present invention is an attempt to solve these problems, and the purpose is to provide an inspection device that can inspect the switching operation while supplying power to the load, regardless of whether there is an abnormality in the switching circuit or semiconductor switch. It is something to do.

E. Means for Solving Problems The present invention provides a first switching means for switching between the output side of each semiconductor switch of the inverter and bypass power supply and the load, and a first switching means for switching between the output side of each semiconductor switch of the inverter and the bypass power supply and the load, and The input terminal of the semiconductor switch and the first
a second switching means for opening and closing between the input side of the semiconductor switch and the load side of the first switching means so as to short-circuit the output terminals of the switching means; a commercial power supply on the bypass side and the power supply side; a third opening/closing means for opening and closing between the input side of the semiconductor switch for the bypass power supply and the input side terminal of the semiconductor switch for the inverter; and comparing means for comparing the voltages on the input and output sides of the power supply and confirming the operation of switching the power supply based on the comparison result.

F Effect The second switching means is closed and the first switching means is opened while the power supply from one power source (inverter) to the load is continued, and then the third switching means is opened.
By opening and closing the opening/closing means and the fourth opening/closing means, respectively, power is supplied from one power supply (inverter) through the semiconductor switch on the bypass power supply side, and under this state, a power supply switching command is issued and the comparison means Check the operation of power supply switching.

G. Embodiment FIG. 1 is a circuit diagram showing an embodiment of the present invention.
MC ₁ is an electromagnetic contactor serving as a first switching means for switching between the connection point of the semiconductor switches TSc and TSi and the load. NC ₂ is an electromagnetic contactor as a second switching means for opening and closing between the input side of the semiconductor switch TSi and the load side of the electromagnetic contactor MC ₁ , and when closed, the semiconductor switch TSi and the electromagnetic contactor are connected.
Short-circuit between the input and output terminals of MC ₁ . An electromagnetic contactor MC _{3 as a third switching means is provided between the bypass power supply and the semiconductor switch TSc on the bypass side, and this electromagnetic contactor MC 3 disconnects} the semiconductor switch TSc from the bypass power supply when opened. .
A magnetic contactor MC ₄ as a fourth switching means is provided between the input side of the semiconductor switch TSi for the inverter and _the input side of the semiconductor switch TSc on the bypass side. When the contactor _MC3 is opened, power is supplied from the inverter 1 to the semiconductor switch TSc on the bypass side. 2 is a matching circuit, and this matching circuit 2 is
The deviation between the voltage on the input side and the voltage on the output side of both semiconductor switches TSc and TSi is extracted. Note that 3 ₁ and 3 ₂ in the figure are insulated circuits. 4 is a comparator, and if the deviation from the matching circuit 2 is larger than a preset setting signal, an output signal is generated to notify of an abnormality in the switching circuit. In this embodiment, the matching circuit 2 and the comparator 4 constitute a comparing means 5 for checking the operation of each semiconductor switch TSc, TSi.

Next, the operation at the time of inspection when switching from inverter 1 to bypass using the apparatus of the above-described embodiment will be described.

First, when an inspection command is issued, the magnetic contactor MC ₂
is closed, and then magnetic contactor MC ₁ is opened. As a result, the input side of the semiconductor switch TSi on the inverter 1 side and the output terminal of the contactor MC ₁ are short-circuited, and power is loaded and supplied from the inverter 1 via the magnetic contactor MC ₂ , and each semiconductor switch
The connection point of TSi and TSc is disconnected from the load. Thereafter, the electromagnetic contactor MC ₃ is opened, and then the electromagnetic contactor MC ₄ is closed. As a result, the power supply to the semiconductor switch TSc on the bypass side is transferred from the bypass side to the inverter 1. Under this condition, a command to switch the power supply to the bypass is issued from the inverter 1, and it is determined whether there is an abnormality in the switching operation. Regarding this judgment, if the switching is performed normally, at least one of the semiconductor switches TSi and TSc will be in the on state during that time.
The potentials between the input and output terminals of TSi and TSc are approximately equal, so the output level of comparator 4 is "L" and is determined to be normal.If switching is not performed normally, for example, it may be switched asynchronously. If switching is not possible, an "H" level signal is output from the comparator 4, and it is determined that there is an abnormality.
If it is determined to be normal, then the electromagnetic contactors MC ₁ to _{MC 4} are operated in accordance with the reverse operation described above. That is, first, the electromagnetic contactor MC ₄ is opened, then the electromagnetic contactor MC ₃ is closed, and the power supply to the semiconductor switch TSc on the bypass side returns to the bypass side. After that, the magnetic contactor MC ₁ is closed, and then the magnetic contactor MC ₂ is opened, and as a result, power is supplied from the bypass side to the load via the semiconductor switch TSc, and the power supply to the bypass side is completed. In this way, the switching operation can be inspected. ends. Note that operations similar to those described above are performed during operation confirmation when switching power supply from the bypass side to the inverter.

Here, the present invention is not limited to a device that switches power supply between an inverter and a bypass, but can be applied to a device that switches power supply between two other power sources. can.

FIG. 2 is a circuit diagram showing another embodiment applied to a device that switches the power supply between two power supplies A and B. In this embodiment, the inspection and On the other hand, it has a function that can perform both checks when switching the power supply from power supply B to power supply A. Switch in Figure 2
SW ₁ and SW ₂ correspond to the first opening/closing means and the second opening/closing means, respectively, and the switches SW ₂ and SW ₄
Both correspond to the third opening/closing means and the fourth opening/closing means. For example, when power is being supplied to the load from the power source A, the switch _SW1 is closed. Further, the switches SW ₂ , SW ₃ and SW ₄ are each switched to the contact a side. Here power supply A
In order to check the operation of switching the power supply from the power supply A to the power supply B, switch SW ₁ is opened, and power is supplied from the power supply A to the load via the switch SW ₂ , and the semiconductor switches TS _A and TS _B are both connected to the power supply. Since power is supplied from A, inspection can be performed in the same manner as in the previous embodiment. Also, if power is being supplied to the load from power supply B and you want to check the switching operation of power supply from power supply B to power supply A, you can do this by switching all switches SW ₂ to _{SW 4} to contact b. can.

H. Effects of the invention As described above, the invention short-circuits the input terminal of one semiconductor switch and the output terminal of the load-side switch, supplies power to the load through this short-circuited circuit, and connects both semiconductor switches to one side. In this system, power is supplied only from the power source of the semiconductor switch, and the presence or absence of an abnormality at the time of switching is checked based on the input/output voltage difference of each semiconductor switch. Therefore, according to the present invention, the switching operation can be inspected while power is being supplied to the load, regardless of whether there is any abnormality in the switching circuit or semiconductor switch. In addition, when switching between an inverter and a bypass power supply, for example, the bypass side is disconnected and power is supplied from the inverter to the semiconductor switch on the bypass side, so even if the semiconductor switch on the inverter side fails, the power supply is switched from the bypass to the inverter. The inverter will not stop due to cross current. Furthermore, when switching the power source, the reliability of the system is further improved because it can be done after confirming that there is no abnormality in the switching operation.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention;
The figure is a circuit diagram showing another embodiment of the present invention, and FIG. 3 is a circuit diagram showing a conventional example. 1...Inverter, TSc, TSi, TS _A and TS _B
... Semiconductor switch, 2 ... Matching circuit, 4
... Comparator, 5 ... Comparison means, MC ₁ ~
MC ₄ ...Magnetic contactor, A, B...Power supply, SW ₁ ,
SW ₄ ...Switch.

Claims (1)

[Scope of Claim for Utility Model Registration] A device for switching the power supply to a load between one power supply and the other power supply connected in parallel with each other by means of semiconductor switches respectively connected to each power supply, and at the time of switching. In a power supply switching inspection device that performs operation inspection, a first opening/closing means opens and closes between the connection point of each semiconductor switch and the load, and an input terminal of one of the semiconductor switches that supplies power to the load and the first switching means. a second switching means for short-circuiting the output terminal of the switching means; a third switching means for opening and closing between the other power source and the input side of the semiconductor switch on the power source side; and a semiconductor switch on the one power source side. Compare the voltage on the input/output side of each semiconductor switch with the fourth switching means that opens and closes between the input terminal of the switch and the input terminal of the semiconductor switch on the other power supply side, and check the switching operation of the power supply based on the comparison result. and a comparing means for closing the second switching means and then opening the first switching means to supply power from one power source to the load via the second switching means, and By opening and closing the switching means 3 and the fourth switching means, respectively, power is supplied from one power supply to the semiconductor switch on the other power supply side, and in this state, a power supply switching command is issued and power is supplied by the comparison means. A power supply switching inspection device characterized by confirming switching operation.